Thiocardenolides II: Synthesis and Pharmacological Evaluation of 3β-Thioacetyl-14β-hydroxy-5β-card-20(22)-enolide

The synthesis of a 3β-thioacetylcardenolide is described. The thioacetate exhibited effects similar to those seen with digitoxigenin acetate on the isolated frog and guinea pig hearts at 1×10−7dilution. In the intact rat heart, the lethal dose was 5mg/kg for the thioacetate and 2.5mg/kg for digitoxigenin acetate. The thioacetate inhibited sodium- and potassium-activated adenosine triphosphatase to the same extent as digitoxigenin, but it was somewhat less inhibitory than digitoxigenin acetate.